Time stamp changing mechanism for mail cancelling systems or the like



1959 P. POLLAK, JR., ETAL 1 TIME STAMP CHANGING MECHANISM FOR MAIL CANCELLING SYSTEMS OR THE LIKE Filed Dec. 5, 1957 3 Sheets-Sheet 1 Ti .E

-ITW I W INVENTORS PH/L /P POLL/1K, J2.

Y EDWARD J LIOPES Nov. 3, 1959 P. POLLAK, JR.. ETAL 2,911,279

TIME STAMP CHANGING MECHANISM FOR MAIL CANCELLING SYSTEMS QR THE LIKE Filed Dec. 5, 1957 3 Sheets-Sheet 2 ATTORNEYS Nov. 3,1959 P. POLLAK, JR.. ETAL 2,911,279

' TIME STAMP CHANGING MECHANISM FOR MAIL CANCELLING SYSTEMS OR THE LIKE 3 Sheets-Sheet 3 Filed Dec. 5, 1957 n m n m u u I m INVENTORS PH/L/P POLL/4K, \f/e, EDWARD 3'. LOPES 4 TTOE/VEVS drums.

United States Patent STAMP CHANGING MECHANISM FOR MAIL CANCELLING SYSTEMS OR THE LH(E Philip Pollak, Jr., ChevyChase, Md., and Edward James Lopes, Washington, D.C., assignors to Emerson Radio & 'Phonograph Corporation, Jersey City, N.J., a corpo- 1 ration of New York Application December 5, 1957, Serial No. 700,861

2 Claims. Cl. 346-141) The present invention relates. in general to mail processing apparatus and more particularly to improved apparatus for cancelling the postage stamp on letters and imprinting the date and time of day thereacross.

With the large volume of mail that is handled by the Post Office Department, the need for fast, efiicient and automatic mail handling apparatus is apparent. There plication, and in the further application referred to therein, letters are automatically conveyed in single file at speeds of the order of 150 inches per second and at rates -of the order of 30,000 per hour past a sensing station wherein each letter is inspected for the presence and position of a postage stamp. As the letters are further .con-

ment is that each first-class letter cancellation must bear the date and time of day of the cancellation, accurate at least to the preceding even half-hour.

7 Therefore the printing device must be periodically reset with the change in time. Because of the great volume of mail and the.

need for a continuously operating device, it would not be feasible to periodically stop the apparatus at such short intervals as every half-hour to reset the printing device.

Jlt is to this general problem that the present invention is directed. I

Accordingly it is an object of the present invention to provide an improved mail or postage stamp cancelling device for imprinting the date and time of day on letters or the like, wherein the device is automatically reset at periodic intervals.

Another object of the present invention is to provide a mail cancelling device for imprinting the date, hour, halfhour and meridian designation on letters or the like wherein said device is automatically reset each half hour.

A further object of the present invention is to provide 'a continuously operating mail processing system wherein a postage stamp cancelling device will accurately imprint the date and time of day without the necessity of stopping the apparatus for resetting the printing wheels at short intervals.

In accordance with the above and other objects of the present invention, a printing or cancellation head or drum semblies. The letters having postage stamps to be can- S 2,911,279 Patented Nov. 3, 195.9

only be reset once each month and correspondingly the date printing wheels need only be reset each twenty four hours. To reset these wheels the machine can be conveniently stopped and the wheels set by hand or other suitable means.

Another wheel on the printing drum services to imprint the hour and has engravings around the edge thereof for printing the numerals from one to twelve. The half-hour printing wheel has alternate characters reading 00 and 303 This wheel must of course he stepped every half hour. The last wheel prints the meridian designation and "has the characters AM, PM, and M engraved along the outer edge representing ante-meridian, post-meridian and meridian (noon) respectively. Thus each half hour, .the half-hour wheelis stepped-to bring a 30 or 700 into printing position. The hour wheel must he stepped each hour to change the hourly printing character designation. The meridian wheel must print an M? at noon and then print PM until half past the midnight hour at which time itmust change to AM. These three wheels areselectively stepped by an actuating pawl which en gages three; ratchet wheels associated respectively with the three printing wheels. The pawl is periodically actuated by an electromagnet which is energized briefly each half hour. The ratchet wheels associated with thethree printing wheels are of such configurations that they cofollowing description of a specific illustrative embodiment thereof taken with the drawings in which:

Fig. l is an elevational view partially broken away of the mail cancelling device of the present invention;

Fig. 2 is a top view of the mail cancelling device partially broken away to show one of the printing drum assemblies;

Fig. 3 is a view of a printing drtun assembly seen from line 33 of Fig. 1; k i

Fig. 4 is a plan view of the actuating pawl;

Fig. 5 is a side view of the actuating pawl of Fig. 4;

. Fig. 6 is a vertical section of the bottom portion of the printing drum;

Fig. 7 is a section taken on the line 7-7 of Fig. 6;

Fig. 8a is a section taken on'the line -8a8a of Fig. .3 showing the meridian printing wheel and its associated ratchet wheel in an illustrative position;

Fig. 8b is a section taken on the line 812-812 of Fig. 3 showing the half-hour printing wheel and its, associated ratchet wheel under the same conditions as Fig. 8a;

Fig. 8c is a section taken on the line 8c-8c of Fig. '3 showing. the hour printing wheel and its associated ratchet wheel under the same conditions as Fig. 8a;

Figs. 9a, 9b and 9c are sections similar to Figs. 8a, 8b and 80 respectively showing the pawl in its actuated position;

Figs. 10a, 10b and 10c are similar to Figs. 8a, 8b and ing wheels and ratchet wheels just prior to a half-pastthe-hour resetting;

celled are conveyed past the printing head where they tions engraved along their edges respectively. It is of course understood that the monthprinting wheel need Figs. 11a, 11b and 110 are similar to Figs. 8a, 8b and respectively showing the relative positions of the printing wheels and ratchet wheels just prior to a noon resetting;

Fig. .12 is section similar to Fig. 80 showing the pawl in its actuated position at the noon hour;

Fig. 13 is a view similar to Fig; 8a showing the relative position of the meridian ratchet wheel and pawl just prior to a twelve-thirty pm. resetting and Fig. 14 is a section similar to Fig. 8a showing thepawl in its actuated position at the twelve-thirty pm. hour.

Referring now to the drawings and more particularly to Figs. 1 and 2 there is shown a pair of horizontally disposed parallel arms and 11 that serve to mount a shaft 12. The shaft is received in holes passing through the arms in a friction fit so that the shaft is non-rotatable. An electromagnet generally indicated by numeral 13 is mounted on the upper surface of arm 11 by means of screws 14. The electromagnet comprises a cylindrical spool 15 of generally U-shaped semi-cross-section to receive the wire turns 16 which are coaxial with shaft 12.

A cancellation printing head or drum generally indicated by numeral 17 is formed of an inner cylinder 18, an upper circular plate 19, and an outer cylinder 21. The inner and outer cylinders 18, 21 and circular plate 19 'forming the printing head 17 may be made integral or joined together by any suitable means. Ball bearing races, one being shown at 23, are located between shaft '12 and the inner cylinder 18 so that the printing head assembly17 is free to rotate about the shaft 12.

The printing head 17 serves to mount a symmetrical set of printing wheel assemblies 24 (illustratively three in number) which are equally spaced around the periphery of the printing drum 17. Each printing wheel assembly 24 is mounted in a U-shaped bracket 25 having bent-over ears 26 and 27. A pair of mounting screws 28 pass upward respectively through the ears 26, 27 of the mounting bracket 25 and are received in respective tapped holes in the upper circular plate 19. A pair of spacers 30 serve to maintain the printing wheel assembly 24 a fixed distance below upper plate 19.

The printing wheel assembly 24 includes six printing wheels 31, 32, 33, 34, 35 and 36 all individually rotatably mounted on a shaft 37 which is received in holes in the side arms 25B, of U-shapecl bracket 25. As shown by the legend in Fig. 2 the printing wheels have characters e11- graved around their peripheries which taken together indicate the month, date and time of day. In addition, the printing head outer cylinder 21- may bear engravings for printing other portions of a complete postal cancellation, such as the city, state, postal zone, year, etc., to-

gether with any desired legend, emblem or design. Accordingly, in the example illustrated, a complete cancellation is repeated three times around the periphery of the head 17. The cancellation is imprinted across the stamp on each letter as the letters are fed past the printing head 17. The apparatus for feeding the letters past the cancelling station and the means for operating the printing head 17 is shown in the above cited application and reference may be had thereto for the details of this apparatus. It is sufficient for the purposes of the present application to state that the postal letters are passed in single file at high uniform speed past a sensing station where the presence and location of a postage stamp on a letter is detected and an electrical pulse signal is produced.

'From the sensing station the letters are then conveyed postage stamp to swing into printing engagement with the envelope as the letter flies by, thereby imprinting the cancellation without diminution of envelope speed. It will be understood that the heads 17 are continuously rotating at an appropriate rate causing their peripheral velocities to be equal to the linear speed of the envelopes passing thereby, so that printing without smudging can be performed. This arrangement is described in the above mentioned Pollak applications.

It is understood that the cancellation imprint should contain the month, date, hour, half hour and meridian (i.e., a.m., pm. and n1.) designation. The month and date wheels 31, 32 and 33 may be conveniently set by hand or other means by stopping the machine at the end of each day. However since a half-hourly stopping of the machine would cause undue delays and vitiate the desired high speed operation, illustratively processing 30,000 envelopes per hour passing at inches per second, the present invention provides automatic means for periodically setting the hour wheel 34, half-hour wheel 35 and meridian wheel 36 without stopping the machine.

Referring now more particularly to Figs. 1, 3 and 6 through 9, the shaft 37 is fixedly mounted in the U- bracket 25 and the six printing wheels are rotatably mounted on this shaft. Each of the printing wheels 34, 35 and 36 to be automatically adjusted has an associated ratchet wheel 38, 39 and 41 respectively. Each ratchet wheel is secured to its associated printing wheel to rotate therewith. Thus as one of the ratchet wheels is stepped or indexed from one position to the next, its connected printing wheel will similarly be indexed. The periodic indexing of the ratchet wheels 38, 39 and 41, and thus their corresponding printing wheels, is achieved by means of armature and pawl arrangements now to be described. A U-shaped armature 42 has a pair of arms 42A which have holes 42B in the outer extremities thereof to receive the shaft 37. As shown in Fig. 3, the shaft 37 has an enlarged head 43 at one end thereof and a washer 44 at the other end which are spaced a distance beyond the arms 25B of bracket 25. A pair of coil springs 45 and 46 are located around the ends of shaft 37 between the arms 25B of bracket 25 and flange 43 and washer 44 respectively. One end of each of the coil springs 45, 46 is received in a notch 26A in the forward edge of bracket ears 26 and 27 respectively. The other end of each of the coil springs is received in a small opening as at 47 in Fig. l, in the respective sides 42A of the U-shaped mount a pawl 49. The pawl 49 has a flat base portion 50 and a pair of upstanding ears 51 having holes through which the shaft 48 passes. Three fingers 52, 53 and 54 extend from the base portion 50 of pawl 49 to selectively engage the ratchet wheels 41, 39 and 38 respectively. A small coil spring 55 (Figs. 2, 8a) is positioned around shaft 48 at one end thereof and is anchored at one end through 'a small hole 56 in the armature 42. The other end of spring 55 is bent over the rear edge of pawl 49 as at 57. It is seen then that the pawl 49 is spring urged in a clockwise direction as seen in Fig. 8a and that relative movement is permitted between armature 42 and pawl 49.

Referring back to Fig. 1, it is seen that upon energization of solenoid 13 the armature 42 will be pulled downward in a counterclockwise direction against the action of springs 45 and 46 (corresponding to a clockwise movement in Figs. 8 to 14). The control means for energizing the electromagnet does not form part of the present invention and it need only be noted that a pulse of current is provided by any suitable means each half hour to energize the electromagnet. A suitable means would be a clock with relay contacts adapted to close on the hour and on the half-hour, for a brief interval which is not critical. Closing such contacts would then connect electromagnet 13 to a suitable source of current for a like interval. Thus the armature 42 will be pulled downward and released each half-hour. As the armature 42 is actuated, it will carry the pawl 49 with it andthe fingers 54, 53 and 52 will selectively engage their associated ratchet wheels 38, 39 and 41 respectively in a manner now to be described.

It is understood that the half-hour printing wheel 35 must be stepped or indexed each half-hour to bring the appropriate characters 00 or 3 0 into the printing position whichis indicated by arrow 58. The wheel 35 there- .fore has these characters 00 and '30 alternately distributed therearound, with preferably six positions for each character, or a total of twelve printing positions, although other convenient numbers of printing'positions ofwheel 35 may be provided as desired.

To accomplish the desired half-hourly stepping of the half-hour printing wheel 35, the half-hour ratchet wheel 39 is provided with a series of six shallow notches 59 alternately arranged with a series of six deep notches 61 the half-hour wheel 35 from one printing position to the v next.

The hour wheel 34 is inscribed with the numerals 1 through 12 equally spaced around its periphery. However this wheel must index but once each hour. The hour ratchet wheel 38 associated therewith has twelve teeth "62 equally spaced around its periphery corresponding to the twelve hourly positions inscribed on the wheel 34. The ratchet wheels 38 and 39 are'so relatively oriented on shaft 37 that upon an hour indexing the half-hour pawl Ifinger 53 will be received in a deep-notch 61 in wheel 39.

Thus the hour pawl finger 54 will engage a tooth 62 of the hour ratchet wheel 38 to cause an indexing of the hour printing wheel 34.

-Figs. 8b, 8c and 9b, 9c illustrate this action. Figs. 8b ,and "8c show the positions of the hour and half-hour printing and ratchet wheels just before the 'hour; these positions, of course, are maintained for the entire halfhour following a half-hour actuation until just before the subsequent hour actuation. For example, they may regis- -ter'8:30.' The armature 42 in this position; is urged upwardly by its springs 45, 46 and the pawl 49 is urged clockwise relative to armature 42 by spring 55 so that the hour .pawl finger 54 rests in the shallow notch of hour ratchet wheel 38 between two teeth 62. As seen in Fig. 5, the three pawli fingers 52, 53, 54 have ditferent angular relations to the pawl body 50, so that. if pawl finger 54 engages a shallow-notch of ratchet wheel 39, the fingers 52 and 54 are held out of direct engagement with their respective ratchet wheels 41 and 38. v

1 Figs. 9b and 90 show the positions of the elements during the brief period that electromagnet 13 .is energized.

Armature 42 has been pulled down, driving pawl 49 down- 1 setto9:00.

Figs. 10b and 100 show the positions ofthe parts after the-electromagnet 13 is de-energized, which continues for the next'half-hour. As seen, half-hour pawl finger '53 now restsin a shallow notch 59 of the half-hour ratchet wheel 39, and this keeps the hour pawl finger 54 in a position where it cannot engage any teeth 62 of the hour ratchet wheel 38. Therefore, uponthe next actuation of armature 42, finger 53 will engage. a shallow notch 59 in -the periphery of the half-hour ratchet wheel 39 as seen inFig. 10b to index the half-hour wheel, but as the end -of-pawl finger '53 engages the bottom of shallow notch 59,

low notch 59 thus serves as a pawl stop with the result, that the hour ratchet wheel fails to index upon alternate actuations'of the armature 42 which corresponds to the half-hour periods. This operation continues cyclically so that'the half-hour wheel steps upon each actuation of the armature '42, while the hour wheel indexes only on every second armature actuation.

Considering now the operation of the meridian printing wheel 36, it is desired that it print M (for meridian) at'the noon hour, followed by PM from half 21 noon through midnight. At half-past the midnight hour, AM must be brought into printing position and remain until the following noon. It is seen then that this is. not a twelve hour cycle, but a twenty-four hour cycle, and thus themeridian printing wheel 36 must function accordingly by providing an M imprint on alternate twelve hour intervals. According to one aspect of the present invention, this twenty-four hour cycle is eifectively converted into a twelve-hour cycle, as will now be described.

The periphery of the meridian ratchet wheel 41 is provided with a series of six notches 63 alternately arranged with a series of six teeth 64. These twelve notches and teeth correspond with the twelve printing positions around the edge of the meridian printing wheel 36. The size of the ratchet wheel 36 and its teeth 64 are chosen in relation to the size and angle of its pawl finger 52 so .thatwheel 3 6'will not be engaged upon actuation of the armature 42 at an ordinary half-hour or hour time. This is readily seen in Figs. 10a, 10b and 10c wherein the positionspf the elements are shown just prior to a half-hour actuation such as would occur at 9:30 a.m. As therein shown, half-hour finger 53 engages a shallow notch '59 to index the half-hour ratchet wheel. The bottom of the shallow notch 59 acts as an arrestor for the pawl 49 so that further downward movement of the armature 42 does notresult in any'further radially inward movement of the pawl. The armature 42 is of course permitted to descend by the yielding action of pawl spring 55. In this condition, pawl finger 52 is radially within the-outer tips of teeth 64 but radially outside the notches .63. It should be particularly noted that a notch 63 of ratchet wheel 41 rather than a tooth 64 is aligned with meridian pawl finger 52 at this time. Hence, upon the half-hourly energization of the solenoid 13 the meridian finger 52 will move clockwise about 30 degrees, but will not engage any notch or tooth of ratchet wheel 41, and will thereafter return to its original position without causing any indexing of meridian printing wheel 36.

Referring to Figs. 8 and 9 it is seen that upon an ordinary hourly indexing, such as would occur just prior to 9:00 p.m., when half-hour finger '53 engages a deep notch 61 in the half-hour ratchet wheel and the pawl '49 is permitted to travel inwardly a greater radial distance, until stoppedby the engagement of hour finger 54 on its ratchet wheel shallow notch 62A, it is still not sufiicient to permit meridian finger 52 to engage the meridian ratchet wheel. At this hourly indexing position, the hour ratchet wheel 38 acts as a pawl stop to prevent indexing of the meridian --further.inward movement of pawl 49 is arrested and hour wheel. In order to insure that there is no engagement 1 at this time between finger 54 and a tooth 62, this finger is bent relative to finger 53 as shown in Fig. 5. The shalwheel 36.

Nowreferring to Figs. 11a, 11b and 110, there is represented the positions of the elements just prior to a noon actuation when it is desired that the meridian printing Wheel 36 shall index. Hour ratchet wheel 38 has a single notch cut in its periphery and the wheel 38 is so oriented on'the shaft 37 that this notch 65 is aligned with finger 54 after the 11:30 indexing, as in Fig. 110. Thus in this position the pawl 49 extends radially inward toward shaft 37 a sufficient distance to permit meridian finger 52 to engage a notch 63in the meridian ratchet wheel 41, and its stroke upon the 12:00 noon energizetion of electromagnet 13 will bring a new printing point M on the meridian printing wheel 36 into the printing position. Fig. 12 shows the position ofthe pawl finger 52 at noon during electromagnet excitation. As soon as *the electromagnet is de-energized, it will return to its '7 normal elevated position as shown in Fig. 13. An important result of the noon actuation is that the meridian ratchet wheel 36 is rotated to a point where one of its teeth 64 is now located in the path of the pawl finger 52 as seen in Fig. 13. Thus, the subsequent actuation of the pawl at 12:30 p.m. will result in an indexing of the meridian ratchet wheel 36, as required to go from 12:00 m. to 12:30 pm. Since half-past noon is a half-hour actuation, the radial movement of the pawl 49 will be determined solely by the shallow notch 59 in the halfhour ratchet wheel 39 as seen in Fig. 10. Thus the teeth 64 of the meridian ratchet wheel are made of such length as to engage the finger 52 even for the smallest radial pawl movement which occurs on the half hour. This engagement is assured by providing meridian finger 52 with a bend relative to hour finger 54 as seen in Fig. 5.

Fig. 14 illustrates the position of the pawl 49 at the extreme position of the half-past noon actuation, while the electromagnet is energized. It is seen that the pawl finger 52 has engaged a tooth 64 to index the meridian printing wheel 36. As this wheel is thus indexed the characters PM are brought into the printing position, and when the pawl returns to the normal position a notch 63 in the meridian ratchet wheel is again aligned with the finger 52 and none of the teeth 64 are located in the path of the finger, as in Fig. a.

It is seen then that the meridian ratchet wheel 36 has two normal or standby positions. A first position is illustrated in Figs. 8a and 10a wherein a notch .63 is radially aligned 'with the finger 52, and indexing is only effected every twelve hours when finger 53 engages a deep notch 61 in the half-hour ratchet wheel simultaneously with the engagement of finger 54 with thenotch 65 in the hour ratchet wheel. The second standby position of the meridian ratchet wheel is illustrated in Fig. 13 wherein a tooth 64 is positioned in the path of movement of finger 52. This second standby position will occur just after indexing the wheel 41 by the engagement of the finger 52 with a notch 63. The meridian printing wheel 36 will therefore index on two successive half-hour actuations every twelve hours, the first of the two index movements occurring when notch 65 in the hour ratchet wheel 38 is engaged by hour pawl finger 54 at noon. This movement will bring the M char actcr into printing position. Upon the next actuation of the armature 42, the meridian ratchet wheel 41 will again index to bring the character PM into printing position. For the next successive twenty-two half-hour aotuations, the meridian wheel 41 will remain in this position until the notch 65 in hour ratchet wheel 38 is again aligned with its associated finger 54. The time of day will then be midnight and the meridian wheel 36 will index on the next stroke. However, the customary postal meridian designation at midnight is PM so that the following printing point on the meridian printing wheel 36 is made to carry the characters PM. As this point is brought into printing position, the meridian ratchet wheel 41 is rotated to its second normal or standby position wherein a tooth 64 is located in the path of movement of the pawl finger 52 as described above. Therefore with the next actuation of the armature 42 at halfpast midnight, the meridian ratchet wheel 41 will receive its second successive indexing and the next point on the meridian printing wheel 36 carrying the character AM" will be brought into printing position. As shown by the legend in Fig. 13, the cycle of characters on successive points of the meridian printing wheel reads M, PM, PD/Ln AM.

The present arrangement has the advantage that the same armature stroke causes the indexing of each of the three printing wheels 34, 35, 36 even though one wheel steps each half-hour, another every hour, and the third only in two successive half hours once each twelve hours. This is provided by the use of three repeats of the printing configuration on meridian wheel 36, where wheels.

the characters AM, M, PM, PM follow each other cyclically three times around the wheel periphery.

Each of the six printing wheels 31, 32, 33, 34, 35 and 36 preferably has twelve printing points around its peripheiy separated by twelve V-notches 66. These notches cooperate with a leaf spring 73 secured by screws 74 on the inner surface of bracket 25 directly below the printing Spring 73 has six spring fingers 74, 75, 76, 77, '78 and 79 each of which has a crimped outer end as at 81 in Fig. 6. The crimped end 81 of each spring finger will be urged into a notch 66 of the aligned printing wheel to maintain the wheels in a fixed position and prevent any gradual creeping which might cause misprinting. In Fig. 6, the hour printing wheel 34 is shown held in position by spring finger 77 engaging a notch 66. Of course the spring fingers have suflicient resiliency to permit smooth indexing of the printing wheels upon actuation of the pawl.

The different degrees of bend imparted to fingers 5'2,

53, 54 as shown in Fig. 5 have the advantage of simplifying the design of ratchet wheels 34, 35, 36 which can thereby have the same radii for corresponding levels. However, this is not essential to the invention, since any wheel radii and either straight or bent fingers may be used while maintaining their relationship as described above.

It is particularly to be noted that the time changes for the printing wheels is effected without affecting the rotation of the cancellation head. The electromagnet coil 13 is symmetrically disposed relative to the axis of rotation of the head, so that the armature 42 will be attracted to the electromagnet regardless of the rotary position of the head, and the device will operate during continuous rotation of the head.

Thus the present invention has provided apparatus for automatically changing the time stamp for postal cancellation or the like, particularly useful with continuously rotating cancellation heads since the time changes are effected without in any way impeding the rotation of the heads.

It will also be understood that the principles of the present invention may be readily extended to provide for automatic change in the day of the month or in the name of the month, by similarly stepping their printing wheels.

While the present invention is particularly useful in connection with the mail cancelling apparatus described in the above-mentioned Pollak applications, it will be understood that it is not necessarily limitedthereto, but may be used generally in other mail cancelling or time changing apparatus. In particular, where noon is indicated by N and midnight by M as in some time printing systems, the same apparatus may be used by having the meridian printing wheel bear the characters AM, N, PM and M in succession, cyclically repeated therearound, in place of the sequence AM, M,"PM, PM illustrated above. I

It will also be obvious that the principles and features of the present invention are not limited to cancelling or printing, but may equally be applied to indicating or registering time of day or other quantities.

Though the present invention has been described with respect to a specific embodiment thereof, it is understood that this is not to be considered as limiting the invention as set forth in the appended claims.

What is claimed is:

l. A postage stamp cancelling device of the character described comprising a printing cylinder, means rotatably supporting said cylinder, a plurality of equally spaced printing wheel assemblies mounted on said cylinder around the periphery thereof, a stationary electromagnet adapted to be periodically energized located symmetrically within said cylinder; each of said printing assemblies including a stationary shaft, first, second and third printing wheels rotatably mounted on said shaft, first, second and third ratchet wheels mounted on said shaft and secured respectively to said first, second and third printing wheels, an armature rotatably mounted on said shaft, first spring means on said shaft connected to urge said armature to a raised position above said electromagnet, pawl means rotatably mounted on said armature, second spring means urging said pawl radially inward of said assembly, said armature being adapted to be actuated upon energization of said electromagnet, said pawl having first, second and third finger positions to selectively engage said first, second and third ratchet wheels respectively, said first ratchet wheel having twelve teethequally spaced around the periphery thereof adapted to be selectively engaged by said first finger, a notch cut in said first ratchet Wheel, said second ratchet wheel having twelve alternate shallow and deep notches adapted to be selectively engagedby said second finger, whereby said second ratchet wheel advances one index positionupon each actuation of the pawl and said first ratchet wheel advances one index position when said second finger is received in a deep notch of said second ratchet wheel, said third ratchet wheel having six equally spaced peripheral notches adapted to be selectively engaged by said third finger, whereby said third ratchet wheel advances one index position from a first normal position to a second normal position when said first finger is received in said first ratchet wheel notch and said second finger is received in a deep notch of said second ratchet wheel, and six teeth equally spaced around the periphery of said third ratchet wheel alternately with said six notches, whereby said third ratchet wheel is advanced one index position from said second normal position to said first normal position upon actuation of said armature.

2. A postage stamp cancelling device of the character described comprising a printing head cylinder, means to rotatably mount said cylinder, a plurality of equally spaced printing assemblies mounted on said cylinder around the periphery thereof, an electromagnet adapted to be periodically energized located within said cylinder; each of said printing assemblies including'a stationary shaft, first, second and third printing wheels rotatably mounted on said shaft, said first printing wheel having twelve index positions equally spaced around the periphery thereof having printing characters from 1 through 12 thereon, said second printing wheel having twelve index positions equally spaced around the periphery thereof having printing characters and 30 alternately arranged thereon, said third printing wheel having twelve index positions equally spaced aroundthe periphery thereof having meridan printing characters cyclically in the order of M, PM, PM, AM thereon, first, second and third ratchet Wheels rotatably mounted on said shaft and secured respectively to said first, second and third printing wheels, an armature rotatably mounted on said shaft, first spring means on said shaft connected to urge said armature to a raised position above said electromagnet, pawl means rotatably mounted on said armature, second spring means urging said pawl means radially inward of said assembly, said armature being adapted to be actuated upon energization of said electromagnet, said pawl having first, second and third fingers positioned to selectively engage said first, second and third ratchet Wheels respectively, said first ratchet wheel having twelve teeth equally spaced around the periphery thereof adapted to be selectively engaged by said first finger, a notch cut in said first ratchet wheel, said second ratchet wheel having twelve alternate shallow and deep notches adapted to be selectively engaged by said second finger, whereby said second ratchet wheel advances one index position upon each actuation of the pawl and said first ratchet wheel advances one index position when said second finger is received in a deep notch of said sec ond ratchet wheel, said third ratchet Wheel having six equally spaced peripheral notches adapted to be selectively engaged by said third finger, whereby said third ratchet wheel advances one index position from a first normal position toa second normal position when said first finger is received in said first ratchet wheel notch and said second finger is received in a deep notch of said ratchet wheel, six teeth equally spaced around the periphery-of said third ratchet wheel alternately with said six notches, whereby said third ratchet wheel is advanced one index position from a second normal position to a first normal position upon actuation of said armature, and resilient means to maintain each of said printing wheels in its respective printing position.

9 References Cited in the file of this patent UNITED STATES PATENTS 875,272 Jackson et a1. Dec. 31, 1907 1,102,795 Perry July 7, 1914 1,339,900 Lewis May 11, 1920 2,120,976 Helsel June 21, 1938 2,355,514 Deane et ah Aug. 8, 1944 2,412,472 Ryan et a1. Dec. 10, 1946 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,911,279 November 3, 1959 Philip Pollak, Jr., et al- It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that'the said Letters Patent should read as corrected below.

Column 2, line 6, for "services" read serves column 5, line 53, for "A the" read At the column 10, lines 31 and 32, for "said ratchet Wheel" read said second ratchet Wheel Signed and sealed this 5th day of April 1960.

(SEAL) Attest:

KARL H; AXLINE ROBERT c. WATSON Attesting Officer Commissioner of Patents Patent No. 2,911,279

November 3, 1959 Philip Pollak, Jr., et al It is hereby certif-ie of the above numbered pate Patent should read as corrected below.

I Column 2, line 6, for

for "A the" read At the ratchet Wheel" read sai Signed and sealed this (SEAL) Attest:

KARL H. AXLINE Attesting Oflicer d that error appears in th nt requiring correction an "services" column 10, d second ratchet Wheel e printed specification d that-the said Letters read serves column 5, line 53,

lines 31 and 32, for "said 5th day of April 1960;

ROBERT C. WATSON Commissioner of Patents 

